Air control vane for blower



Dec. 10, 1957 E. K. SMITH 2,815,900

- AIR CONTROL VANE FOR BLOWER Filed Nov. 1. 1954 222! K; Jmz'f/z 6 MMHZHFMW 5 W? 04.2 94:

United States This invention relates generally to liquid fuel burners and more particularly to an oil burner of the gun type having novel air control means for directing the air supply prior to discharge from the blower.

In the operation of conventional gun-type oil burner installations, the combustion chamber and associated stack of the furnace usually exhibit certain draft characteristics which cause the combustion flame to burn either to the right or left of center. This effect may also be caused by irregularities in the shapes or inaccuracies in the assembly of the various oil and air handling parts. Such shifting of the flame away from a center position results in a non-uniform pattern of combustion, and is highly undesirable. I have found that by particularly positioning an adjustable air diffusion control vane within the blower housing, it is possible to sufficiently compensate for the inherent draft characteristics of the installation and the barrier effects of the various parts in the burner blast tube so as to effect a centering of the flame.

Although various deflectors and vanes have been employed in the past to effect direction of the blower air in a desired manner, the positioning of such means has been either within the burner blast tube, or within the blower housing at a point closely adjacent the air discharge outlet from the blower into the blast tube. By the present invention, I contemplate a novel operative positioning of an air deflection means, whereby the blower air is controlled at a remote location substantially back within the blower housing.

It is a primary object of this invention, therefore, to provide an air diffusion control vane for a gun-type oil burner which is operative to direct the discharge of blower air into the blast tube in a desired manner for compensating unbalanced flame conditions to center the burner flame, without interrupting continuous burner operation.

It is another object of this invention to provide an air diffusion control vane which is manually adjustable to permit draft compensating and flame centering over a range of firing rates and draft conditions.

It is a further object of this invention to provide an air diffusion control vane which is particularly positioned within the blower housing in the region rearwardly of the blower fan rotor shaft and above the blower fan blades.

It is still another object of this invention to provide a burner construction employing a substantially reduced blast tube length, thereby minimizing the floor space required for a practical installation, without the usual consequences of non-uniform air flow and asymmetrical flame pattern, by means of a novel air diffusion control vane.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my Air Diffusion Control Vane for Oil Burners whereby the objects contemplated are obtained as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawing, wherein:

Figure 1 is a vertical cross-sectional view in side elevation of the blast tube and blower housing of a gun-type oil burner embodying a first form of air diffusion control vane, constructed in accordance with the present inhidden;

aterit 2,815,900 Patented Dec. 10, 1957 Figure 2' is an end view, partly broken away and in section, in the direction 22 of Figure 1;

Figure 3 is a fragmentary cross-sectional view taken substantially as indicated along the line 33 on Figure 1;

Figure 4 is a fragmentary vertical cross-section of the blower housing of a gun-type oil burner, showing a second, modified form of air diffusion control vane;

Figure 5 is a fragmentary cross-sectional view taken substantially as indicated along the line 5-5 on Figure 4; and

Figure 6 is a perspective view of the air diffusion control vane illustrated in Figures 4 and 5.

Referring nowto the drawing,.I have illustrated in Figure 1 a gun-type oil burner of the type including an elongated cylindrical blast tube 10. The blast. tube 10 is provided at its rear end with an outwardly extending, peripheral mounting flange 12 for rigidly securing the blast tube 10 in alignment with an outlet opening 14- of an air fan or blower housing 16.

The blower housing 16 is of generally conventional form within which a squirrel-cage type of fan or blower wheel 18 is mounted. The fan 18 is of the well-known form providing a plurality of angularly disposed, peripheral fan blades 20. The fan 18is mounted on a rotor 22 which is suitably secured to and driven by the draftshaft of a motor (not shown). The relative spacing between the periphery of the fan 18 and the inner walls of the housing 16 serves to define a scroll chamber 24.

It is important that the top of the fan 18 be positioned well up into the height of the outlet 14, as shown, so that the air flow from the blower is driven directly into the blast tube 10. This location of the blower 18 within the housing 16, in particular relation to the discharge outlet 14 and the blast tube 10, is essential in order to permit the air diifusion control means of this invention to be located at the first point of air discharge from the fan blades Zti, as will be hereinafter described in detail.

An oil supply tube 30 extends longitudinally within the blast tube 10. The tube 30 terminates at its forward end in an oil spray nozzle 32. A suitable opening 34 is provided in the side wall of the blower housing 16 through which the rear end of the oil tube 36 extends outwardly for connection to an oil supply pump (not shown) in the well-known manner. A pair of ignition electrodes 36, having insulating carriers 37, are provided in longitudinally extending relation above the oil tube Ell).

The oil tube 30 and the electrodes 36 are fixedly positioned and supported by a baffle plate 38. The baflie plate 33 provides an obstruction to the flow of air through the blast tube 10, and defines an annular flow passageway 40 therearound.

An end ring assembly 42 is carried by the blast tube 10 at its forward end. The assembly 42 includes a plurality of helical air-deflection vanes 44, a throat-forming ring 46, and a collar flange 48.

The air deflecting and baflling structure shown in Figures 1 and 2 of the drawing are set forth and described in detail in my co-pending application, Serial No. 466,061, filed Nov. 1, 1954, now Patent No. 2,790,- 490. Reference may be had to my said co-pending application for a more detailed explanation of the relationship of various air deflecting parts and the air flow pattern through the blast tube.

The novel feature of the present invention is particularly directed to'the provision of an air diffusion control vane. In Figures 1 and 3 of the drawing I have illustrated a first embodiment of my invention, wherein the air diffusion control vane is in the form of a generally rectangular rudder or plate-50 formed from relatively thin sheet metal. A screw-threaded pivot shaft 52 extends downwardly through a top wall portion of the blower housing 16, and rigidly carries the control vane 50 at its lower end. The pivot shaft 52 is suitably screwthreaded for cooperation with a lock nut 54 and a bearing 55. Suitable adjustment of the shaft 52 and the lock nut 54 will serve to adjust the position of the lower edge of the control vane 50 relative to the fan blades 20. In practice, the spacing between the bottom edge of the rudder 50 and the lateral edges of the blades 20 is preferably equal to about A: inch.

A manual turning knob and indicator 56 is rigidly connected to the upper end of the pivot shaft 52. The knob 56 permits manual turning of the pivot shaft 52 to permit angular positioning of the control vane 50 in a manner to be hereinafter described. Further, the knob 56 provides an indicator means in parallel alignment with the plane of the control vane 50 to permit easy visual determination of the angular position of the control vane 50 within the blower housing 16.

As best seen in Figure 3 of the drawing, the pivot shaft 52 extends through the blower housing 16 substantially midway of the housing width. It is important that the pivot shaft be positioned at a point closely adjacent the rear wall of the blower housing 16 so as to permit the control vane 50 to be disposed across the scroll chamber 24 substantially in the manner shown. In particular, the control vane 50 is positioned rearwardly of the fan rotor 22, and with the effective area of its surface located to one side of the vertical center plane of the blower housing 16.

By securing the pivot shaft 52 to the vane 50 adjacent its rear edge, as shown, the forward edge of the vane may be rotated through the arcuate path indicated by the arrows in Figure 3. Pivotal rotation in this manner permits an angular positioning of the plane of the vane 50 across a portion of the normal air flow path shown by the arrows in Figure 1. The incoming air side of the blower is indicated by the arrow at the top of Figure 3.

It will be apparent that by manual turning of the control knob 56, the plane of the control vane 50 may be angularly positioned across the normal air flow path to effect varying degrees of air deflection. Assuming that the burner is in operation at a particular firing rate, and assuming that the natural draft characteristics of the installation under such operating conditions ordinarily cause a shifting of the burner flame to one side of the center, the knob 56 may be rotated in a corresponding direction until a proper position has been determined which is effective to cause a centering of the flame.

In actual practice, I have found that the causes of flame asymmetry may be divided into two general classifications. The first of these classifications includes obstructions or disruptions affecting the uniformity and symmetry of the air diffusion within the blast tube supplying air to the combustion zone. The second includes irregularities in the oil supply and the form of the spray cone. In general, air obstructions within the blast tube leading from the blower housing to the combustion zone are the most frequent cause of flame asymmetry, and I have found that this condition is worsened by the air flow helix common at the intake rim of a squirrel cage type of fan. This problem is best compensated for by positioning the effective deflecting surface of the vane 50 between the vertical center plane of the blower housing 16 and the side wall which constitutes the incoming air side of the blower housing. Such a position of vane adjustment is shown in Figure 3. For example, by positioning the vane th at an angle of about 30 with respect to the longitudinal center axis of the blower housing, the air flow helix is sufficiently upset at the incoming side of the housing 16 to have a considerable effect upon the position of the blower flame. Such adjustment will serve .to center a substantially displaced flame.

Conversely, if the controlling cause of flame asymmetry is the result of oil tube irregularities, effective compensation is generally achieved by positioning the effective deflecting surface of the vane between the vertical center plane of the blower housing 16 and the side wall opposite the incoming air side.

In Figures 4-6 of the drawing I have illustrated another form of air diffusion control vane 60. I employ the same reference numerals in Figures 46 to indicate parts which are identical to those illustrated in Figure 1. As best seen in Figure 6, the second embodiment of my air control means comprises a relatively thin strip of metal 62. The terminal ends of the strip 62 are formed with downwardly turned ears 64. Midway of the length of the strip 62, a triangular-shaped deflector surface 66 extends downwardly from the forward edge and at right angles to the plane of the strip 62. Suitable slots are cut through the side walls of the housing 16 as indicated at 68 in Figure 5. In this manner, the strip 62 may be slid transversely through the blower housing 16 from side to side so as to effect variable positioning of the deflector surface 66 as shown in dotted lines in Figure 5. The ears 64 serve as stop means to retain the strip 62 in sliding relation within the housing 16.

I have found that the selection of a triangular deflector surface 66, positioned in a plane substantially at right angles to the direction of air flow upwardly through the housing toward the discharge outlet 14, provides a deflector means which performs with substantially the same effect as the rudder type of air control vane 50 which I have shown in Figures 1 and 2. By sliding the strip 62 through the housing 16, the deflector surface 66 may be located in various positions of adjustment for effecting the desired air deflection for flame centering under various operating conditions.

It should be noted that the orientation of the deflector surface 66 at right angles to the direction of air supply flow slightly reduces total air volume as compared to the use of the pivoted vane of Figures 1 and 3. If such a reduction of air volume is undesirable in a particular installation, the vane may be formed so as to twist or incline the surface 66, and thereby position it at an angle across the direction of air supply flow.

It is necessary to provide a minimum blast tube length so that there will be a sufficient distance in which to effect adjustment of the air flow which is obstructed by such irregular barriers as the oil supply tube 3t) and electrode insulators 37. In a burner of the type shown in the drawing, and described in detail in my aforesaid copending application, a minimum distance of about 8 inches is ordinarily required from the point of fan cutoff, indicated at 7 0 in Figure l, to the discharge mouth of the blast tube. I have found that by positioning an air diffusion control vane within the blower housing in the region of the first point of air discharge from the fan blades, as shown, there is a significant effect upon the air flow pattern as it is discharged from the blower housing 16 into the blast tube It The use of a control vane in this manner permits a substantial reduction in the required blast tube length, without adversely affec ing the flame.

A tube distance from the fan cut-off to the blast tube discharge mouth of 6 inches or less may be employed. A reduction in tube length of about 2 inches or more may be attained in a burner installation of the type herein disclosed. Although such a reduction of blast tube length is illustrative, it will be understood that similar reductions in blast tube length are possible for other guntype burner installations employing a control vane in the manner of the present invention.

The pivotal type of vane 50 shown in Figures 1 and 3 of the drawing, and the slidable type of vane 66 shown in Figures 4 to 6 of the drawing, are co-related to each other in the manner of their adjusting movement across the transverse width of the fan 18. Each type of vane provides a generally planar obstructing surface, and each necessarily defines a geometric center point. The imaginary distance, in a perpendicular direction, from such geometric center points to the general plane of the blower housing air inlet varies as each of the respective vanes are selectively adjusted. The geometric relation between the two forms of vanes and the blower housing air inlet, as well as the relation between the vanes and the transverse width of the fan, may therefore be defined in terms of an average perpendicular distance between each vane and the plane of the air inlet.

It will appear, therefore, that my novel air diffusion control vane serves to provide an additional compensating obstruction to the normal pattern of air movement through a burner having characteristics which result in an asymmetrical flame. By means of my particularly and adjustab-ly positioned control vane, it is possible to selectively establish an unsymmetrical pattern of air diffusion. In this way, an initial asymmetry is deliberately created to over-ride or compensate the subsequent downstream asymmetry which is characteristic of the particular burner, thereby balancing the two effects against each other and providing a symmetrical flame pattern. It will be apparent that I have provided a simple manual adjustment which enables an operator to readily effect balanced adjustment of the flame pattern during burner operation.

Changes may be made in the construction and arrangement of the parts of my air diffusion control vane for oil burner without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical improvements which may be reasonably included within their scope.

What I claim as new and desire to obtain by Letters Patent of the United States is:

1. A blower for use with a gun-type burner, comprising a housing having a forward discharge outlet adapted to communicate with the blast tube of a burner and having an air inlet at one side adapted to admit a supply of air to said housing, a rotary fan disposed within said housing and mounted on a drive shaft extending transversely of said housing and substantially coaxial with said air inlet, an air control vane comprising a planar deflecting surface pivotally mounted within said blower housing rearwardly of said fan shaft, said vane being pivoted about a point adjacent its rear end to permit its forward end to be swung through a transverse arcuate path for selectively positioning said deflecting surface across the path of air flow from said fan toward said housing discharge outlet at a remote location substantially back within said housing, thereby permitting a predetermined initial air flow disturbance to be selectively introduced for compensating downstream air flow asymmetry.

2. A blower for use with a gun-type burner, comprising a housing having a forward discharge outlet adapted to communicate with the blast tube of a burner and having an air inlet at one side adapted to admit a supply of air to said housing, a rotary fan disposed within said housing and mounted on a drive shaft extending transversely of said housing and substantially co-axial with said air inlet, an air control vane comprising a planar deflecting surface fixedly pivotally mounted within said blower housing entirely rearwardly of said fan shaft, said vane being pivoted about a point adjacent its rear end to permit its forward end to be swung through a transverse arcuate path for selectively positioning said deflecting surface across the path of air flow from said fan toward said housing discharge outlet at a remote location substantially back within said housing, thereby permitting a predetermined initial air flow disturbance to be selectively introduced for compensating downstream air flow asymmetry.

3. A blower for use with a gun-type burner, comprising a housing having a forward discharge outlet adapted to communicate with the blast tube of a burner and having an air inlet at one side adapted to admit a supply of air to said housing, a rotary fan disposed within said housing and mounted on a drive shaft extending transversely of said housing and substantially co-aXial with said air inlet, an air control vane comprising a planar deflecting surface mounted within said housing transversely thereof and rearwardly of said fan shaft, said vane being slidable transversely across said housing for selectively positioning said deflecting surface in the path of air flow from said fan toward said housing discharge outlet at a remote location substantially back within said housing, thereby permitting a predetermined initial air flow disturbance to be selectively introduced for compensating downstream air flow asymmetry.

4. A blower for use with a gun-type burner, comprising a housing having a forward discharge outlet adapted to communicate with the blast tube of a burner and having an air inlet at one side adapted to admit a supply of air to said housing, a rotary fan disposed within said housing and mounted on a drive shaft extending transversely of said housing and substantially co-axial with said air inlet, an air control vane comprising a planar deflecting surface of triangular area mounted within said housing at right angles to the longitudinal axis thereof and entirely rearwardly of said fan shaft, said vane being slidable transversely between the sides of said housing for selectively positioning said deflecting surface across the path of air flow from said fan toward said housing discharge outlet at a remote location substantially back within said housing, thereby permitting a predetermined initial air flow disturbance to be selectively introduced for compensating downstream air flow asymmetry.

5. A blower for use with a gun-type burner, comprising a housing having a forward discharge outlet adapted to communicate with the blast tube of a burner and having an air inlet at one side for admitting a supply of air to said housing, a rotary fan disposed within said housing and mounted on a drive shaft extending transversely of said housing and substantially co-axial with said air inlet, an air control vane mounted within said housing substantially entirely rearwardly of said fan shaft, said vane providing a planar deflecting surface of substantial transverse area disposed across the path of forward air flow from said fan toward said housing discharge outlet, mounting means whereby said control vane is adjustable to vary the average perpendicular distance between said control vane and the plane of said blower housing air inlet, thereby enabling selective positioning of said control vane across the transverse Width of said fan to deflect and guide said forward air flow at a remote location substantially back within said housing, thereby permitting a predetermined initial air flow disturbance to be selectively introduced for compensating downstream air flow asymmetry to produce balanced adjustment of the flame pattern during burner operation.

6. The combination of claim 5, wherein said air control vane is disposed substantially entirely above said fan shaft.

7. The combination of claim 5, wherein said air control vane is positioned substantially entirely above said fan.

References Cited in the file of this patent UNITED STATES PATENTS Re. 20,668 Seeling Mar. 8, 1938 1,608,938 Henshall Nov. 30, 1926 2,001,522 Chester May 14, 1935 2,215,281 Von Haase Sept. 17, 1940 2,463,769 Shinman June 21, 1949 2,634,806 Hirtz Apr. 14, 1953 2,645,411 Amdler July 14, 1953 

